Heretofore, many efforts have been made to develop an effective and inexpensive litter for animals, especially household pets, particularly cats. Thus it has been disclosed in various patents to use alone or in various combinations urine sorptive materials, odor-inhibiting or control chemicals or materials, antioxidants, microbial inhibitors, surfactants, dyes, antistatic agents, flame retardants, binders, encapsulants, neutralizing agents, weighting or density control agents, and other materials. Representative of the many materials disclosed to provide one or more of these characteristics are: siliceous minerals such as natural or synthetic clays (bentonite, attapulgite, fuller's earth, sepiolite, kaolin), diatomaceous earth, mica, talc, sand, finely divided quartz, vermiculite, perlite, fly ash, pumice, zeolite molecular sieves, opalite, bottom ash, boiler slag, synthetic porous silicas and silicates, hydrophobic microporous crystalline tectosilicates of regular geometry having aluminum-free sites in a siliceous lattice, and the like; natural or agriculturally-grown materials and by-products thereof, such as chlorophyll-containing materials (alfalfa, algae, broome grass, timothy grass, metallic chlorophyllin salts, stems and leaves of leaf meal such as ipilipil niseacacia, etc.), peanut shells, cedar, wood shavings, sawdust, wood flour, bagasse, corncobs, sugar beet pulp, citrus pulp, alphacellulose fiber stock, sulphite cellulosic paper stock, waste paper, paper sludge, hay, husks, bark, straw, gelatinizable carbohydrates, sunflower hulls, partially pyrolyzed cellulosic materials, sagebrush, sorghum, cotton seed hulls, popcorn, peat moss, tomato pumice, grain, potato, cereal or grain hulls such as corn, rice, wheat, oats, and the like, apple pulp and grape pulp; foamed plastics (polystyrene, polyurethanes, phenolic resins, cellular cellulose acetate, etc.); porous plastic beads; cloth; synthetic sorptive granules based on commercial grade plaster (calcium sulfate dihydrate); wax or paraffin coated hydrophobic substantially nonabsorbent and nonwater wettable granular material; porous inorganic material which has been uniformly contacted with a gaseous or liquid acidic substance to neutralize alkalinity therein and provide a pH between 5.8 and 6.2; porous inorganic material treated with a water-soluble zinc salt and having a pH from approximately 7 to 9; absorbent pads; calcium carbonate; Portland cement; activated carbon; alumina; coal residues; recycled molasses serum; in-situ polymerized monomer or monomers containing at least one acidic functional group present in the molecule; water soluble or dispersible materials having colloidal properties in water including silicates, preferably alkali metal silicates, pyrophosphates, preferably alkali metal pyrophosphates, polysaccharides, preferably cellulose derivatives, alginates, or starch; polyvinylpyrrolidone; anhydrous sodium sulfate; citric acid; sodium chloride; sodium or ammonium persulfate and a buffering agent; water absorbent polymers; adhesive-type soluble lignin pelletizing aid; cyclodextrin; thermoplastic polymers, crosslinkable natural gums such as the polygalactomannan gums, xanthan gum, or alginate; pheromone-like attractant substances; a veterinary composition for preventing feline urological syndrome; Plaster of Paris, calcined alkaline earth metal oxides; aluminum sulfate; carbonates, bicarbonates; hydrogen phosphates; benzaldehyde green; rose bengal; certain quaternary ammonium compounds; proprionates; N-alkylpyridinium proprionates; halogenated aromatic hydrocarbons; undecylenic acid; aldehyde derivatives, thiocyanates; carbamates; azo chlorides; modified phenols; oxyalkylated alkylphenols; alkyl sulfate salts; alkylbenzene sulfonate salts; oxyalkylated alcohols; water soluble or dispersible gums and polymers, such as guar gum, micro-crystalline cellulose, pregelatinized starches, methacrylic and acrylic polymers and copolymers, cellulose derivatives (carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose), polyvinyl alcohol, polyethylene oxides, carbohydrates, and proteins; camphane derivatives; various aromatic oils such as pine oil, citrus oils; oil of cloves, and cinnamon oil; menthol; camphor; sodium dihydrogen phosphate; potassium dihydrogen phosphate; potassium acid phthalate; cherry pit extract; certain hydroxyamic acids and salts thereof; perfumes; fragrances; vitamin E; chlorine dioxide; sodium bicarbonate; gypsum; sagebrush oil; microencapsulated fragrance or deodorizer; salts of transition metals of Group Ib or Group IIb of the periodic table of the elements; ferrous sulphate hyptahydrate; borax; and p-hydroxybenzoate.
In the last 10 years or so there has developed a new type of cat litter which "captures" the urine in a "ball" or "clump" of litter which can be scooped from the nonwetted litter for easy removal. See for example the following U.S. patents, incorporated herein by reference: 4,685,420 (Stuart); 5,000,115 (Hughes). These so-called "clumping" litters have been based on one or more clays generally having a particle size within the range from about 297 microns to about 2000 microns. Although these clumping litters have been a vast improvement in eliminating the waste before it generates obnoxious odors, these clumping litters still possess one or more undesirable properties or characteristics. These include: high bulk density; poor clumping (poor cohesiveness of the wetted litter); poor urine sorption capacity; excessive wicking or sorption or the urine into the bulk of the litter before the wetted ball of litter is removed.
Thus there is still a need for a superior litter which eliminates or reduces the odors associated with animal urine.
I have now discovered that the sorption capacity of clays which exhibit osmotic swelling can be dramatically increased by admixing therewith a particulate cellulosic material. The sorption capacity of the admixture is synergistically increased as compared to the calculated sorption capacity of the clay and the cellulosic material at their respective concentrations. Furthermore the bulk density of the admixtures are synergistically decreased as compared to the calculated bulk density of the clay and the cellulosic material at their respective concentrations.
Thus it is an object of this invention to provide a method of increasing the sorption capacity of clays which exhibit osmotic swelling.
Another object of this invention is to provide a clumping sorbent having superior sorption capacity and sufficient cohesiveness when wetted with an aqueous liquid, such as urine, to be easily separated from the nonwetted sorbent particles.
Another object of this invention is to provide a clumping cat litter having a bulk density from about 0.54 to about 0.96 g/cc and a sorption capacity greater than 1.0 cc/g, the litter containing sufficient clay which exhibits osmotic swelling to provide sufficient cohesiveness for easy removal of wetted litter from a litter box, and insufficient of such clay to prevent the disintegration of the litter upon aging in water.
These and other objects of the invention will be readily apparent to one skilled in the art as the description thereof proceeds.
While the invention is susceptible of various modifications and alternative forms, specific embodiments thereof will hereinafter be described in detail and shown by way of example. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but, on the contrary, the invention is to cover all modifications and alternatives falling within the spirit and scope of the invention as expressed in the appended claims.
The compositions can comprise, consist essentially of, or consist of the stated materials. The method can comprise, consist essentially of, or consist of the stated steps with the stated materials.